


Hello, Flying Fatality

by stars_inthe_sky



Category: Brooklyn Nine-Nine (TV), Buffy the Vampire Slayer
Genre: 5 Things, 5 Times, Alternate Universe - Buffy The Vampire Slayer Fusion, Alternate Universe - Vampire Slayer, Buffy the Vampire Slayer References, Crossover, Crossovers & Fandom Fusions, Gen, Team Dynamics, Vampire Slayer(s), Watchers
Language: English
Status: Completed
Published: 2015-06-05
Updated: 2015-06-05
Packaged: 2018-04-02 21:07:15
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 3,701
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4073887
Author URL: https://archiveofourown.org/users/stars_inthe_sky/pseuds/stars_inthe_sky
Summary: <blockquote class="userstuff">
              <p>Five times someone at the Nine-Nine found out that Rosa was the Brooklyn Slayer, and one time no one did.</p>
            </blockquote>





	Hello, Flying Fatality

The guy comes out of nowhere, as far as Rosa can tell. Stacy screams, Ruomei freezes in place, and Rosa punches him in the neck and then whacks him with her tote bag. The would-be mugger stumbles back, ignoring her loose pointe shoes and leotards, and then rounds on her with an actual snarl. Weirdo.

She changes her mind when he socks her in the gut, harder than her sisters had ever hit her growing up.

“Run! I’m fine!” she coughs at her classmates, and they do. Their attacker is more interested in Rosa anyway. It’s been years since she was in an actual fight with anyone besides her fellow ballerinas—thus the probation she's probably about to further jeopardize—but she’s fast and she’s strong and her muscle memory is practically eidetic at this point. “What do you want, loser?”

He grins, and Rosa feels an uncharacteristic pit form in her stomach as his face _changes_ into something wrinkled and sinister. “You.”

She catches sight of his awful disco-era polyester shirt in the sliver of streetlamp light in the alley and meets his animalistic eyes with an evil grin of her own. “Nope.” She knees him in the nuts, and he shrieks and curls into himself, but before she can even consider making her own escape, his hand curls around her bicep, yanking her back toward him.

Rosa spins into his pull, landing a solid jab on the ridged skin between his eyes, and he seems surprised enough by the hit that he lets go of her, so she follows up with another punch. She feels his nose break beneath her knuckles, but no blood comes out. “Creepy.”

The guy huffs, “Who you calling creepy?” He lurches back at Rosa, but before he can grab her again, the biggest human she has ever seen barrels into the man, tackling him to the ground. Rosa just stares blankly as the newcomer—a hulking and noticeably obese police officer—lifts himself off of his target and rises, dusting off his uniform.

“What the actual hell?” she asks.

He smiles like it’s Christmas and, panting, extends his massive hand for her to shake, which she doesn’t. “Officer Terry Jeffords with the NYPD. Heard a scream, saw a couple of girls running away. You’ve got some nice moves for someone with an American Ballet Academy tote.”

She reddens. “You would, too, if you grew up with my sisters. But—”

Before Rosa can reach punctuation, the bad guy springs up behind Jeffords and hooks an arm around the larger man’s neck. He must be stronger than he looks, because Jeffords starts to choke almost immediately.

Rosa doesn’t even think; she darts around and yanks the criminal off of Jeffords, slamming him into the pavement again. He rebounds immediately, but she’s ready this time; she cuts off the next fist he throws with a crescent kick. “What the hell?”

“He’s a vampire! You have to—” Jeffords’s attempt at explanation is cut off by wheezing, and he bends over to catch his breath.

“Am not!” the mugger insists, but his too-long teeth and the way his eyes keep flickering toward her neck make her wonder if Jeffords has a point. Then the guy—creature of the night—whatever—aims a roundhouse kick at her head, and she catches hold of his shoe with both hands and twists. He starts to fall again, and she whips around into a fouetté, putting more strength behind her raised leg than she’s usually allowed. When her heel comes around, it rams him in the chest, throwing him off-balance again, and she shoves him into a still-panting Jeffords. Unfortunately, Jeffords is so big that the other guy basically bounces off of him and falls back toward Rosa.

This is getting stupid, and she groans audibly, but Jeffords interrupts her by throwing a stick at her face and saying, “Catch!”

The stick is sharpened to a point at one end and smacks neatly into her palm like it was made to fit there. Rosa blinks at it for a second, because…really, what?

“Get him in the heart!” Jeffords adds, and he’s either not a real cop or a very bad one, but suddenly the maybe-vampire is grabbing her by the shoulders. His mouth is wide open, his canines are freaky, and there’s no way Rosa’s getting out of this otherwise.

He yanks her to him, but she gets her hand up just in time—the stake goes into his chest with the force of his pull, and he vanishes in a cloud of dust.

“Huh.” Rosa stares down at the small pile of ashes and shuffles her feet to get some of the mess off her shoes. She looks back at the weapon in her hand and then to Jeffords. “Didn’t know I could do that.”

He beams at her like a proud parent. “Damn right you can! Looks like you’re the New York Slayer—everybody’s been trying to locate you for the last few years! That explains the growth spurt I bet you had a couple of years ago—like you just got really strong overnight, right? And the natural talent for ass-kicking.”

“How could you possibly know—Slayer? What?”

Jeffords’s smile just gets bigger—and slightly more insane—but it’s oddly comforting. She gets the sense that, like it or not, she’s just made a friend. “Destiny called you, whoever you are, and something out there thinks you were meant to keep people safe…and, you know, hit bad guys and kill demons.”

***

The whole Academy class goes out for beers after they pass their final round of certifications, and Rosa is having a decent time until Terry texts her to say he and his partner just found a barely-conscious busboy with neck wounds two blocks away and that she should probably keep an eye out for vamps.

He may technically be her Watcher—and one of the few people who can counter her punches without breaking anything—but this is one of his least helpful texts ever, and she rolls her eyes. Time to patrol the entire neighborhood. In the meantime, she can look forward to being a real cop and actually getting paid for doing this job, hopefully at Terry’s precinct so he can keep the bureaucracy out of her way.

Rosa looks up from her phone just in time to see Jake Peralta, one of the most annoying but least awful people in her class, being led out of the bar by a squat blonde with an expensive-looking dress and unnaturally pale skin. If she squints, Rosa can see bits of dried blood on the hem of the woman’s skirt. Case solved, though she will never understand why certain segments of the undead population go from the grave straight to Fifth Avenue. There have got to be better things than clothing to threaten salespeople for, and clothing that snug means this vamp won’t even be able to give her a good fight.

She closes her tab and sprints after Jake and his new friend, not bothering to say goodbye to any of the others. The vampire has steered him to a smaller park a couple of avenues over, with enough trees for discretion, and Rosa silently thanks Terry for making her hone the Slayer sense that lets her track the undead.

She finds the pair braced against a tree; the vampire already has her teeth in Jake’s neck, and the expression on his face suggests he can’t quite seem to figure out if this means he’s scoring with a pretty woman or about to die. Rosa rolls her eyes, ditches her jacket and purse under a bench, and walks right up to slam her left fist into the vampire’s temple. The demon stumbles away, her teeth ripping messily out of her prey’s skin, and she turns on Rosa with a snarl, teetering on her stilettos.

Rosa barks, “Get out of the way, idiot!” at Jake, and he jumps back, still bleeding from the neck, as Rosa blocks the vampire’s punch and flings a kick into her gut.

“Oh, come _on_ ,” the demon grumbles. “Bitch, I’m just hungry.”

“Yeah, bet that’s what you told the busboy over on Sixth, too,” Rosa retorts, ducking the vamp’s elbow and dropping down to balance on her hands, so she can kick it with both feet.

“So? You know how Chinese food—” The vampire tumbles over midsentence with a yelp of protest.

Rosa realizes belatedly that her stakes are in her bag, and she jumps back into a fighting stance as her opponent staggers up. Rosa goes in for another swing and shouts, “Peralta—stake—bag—bench—now—” in between jabs. She can hear him fumbling for a second, but before long the familiar whirr of smooth wood flying through the air reaches her ears.

The vampire lunges for the stake, but Rosa gets it first and slams her into the dirt. There’s several long seconds of full-body struggle, but the vampire dusts easily once she lines the stake up with her target’s heart. Rosa winces as she falls through the six inches of empty space where the vampire had been and hits the ground herself.

“Oh my _god_ , that was _awesome_!”

Rosa scowls. She pulls herself up with a grunt and turns to face Jake. “What were you thinking? You’re a cop; you didn’t notice the _blood_ on her?”

He squeals with delight, apparently unconcerned about the neck wounds or the recently expired vampire. “Technically not yet a cop, also not on duty, _and_ she looked hot and not, you know, evil and bitey before. What did you just _do_?”

Rosa snatches her stuff from under the bench behind him and stalks away. “Saved your ass. Go home.”

Unfortunately, Jake catches up with her after about half a block and jogs in front of her. “Wow, you walk _really_ fast. But seriously. Was that an actual _vampire_? Trying to _suck my blooood_?” His Dracula accent is terrible, but he continues in his normal voice, “Is that a thing now? Because that _so_ did not get covered in training, but you seemed like you knew what you were doing…”

“Ugh, stop.” She puts up a hand and his face smacks into her palm, but at least he stops talking. “Yeah, it was a vampire. I’m a vampire slayer; that’s why I joined the NYPD, so people would pay me and leave me alone so I could, like, slay. And protect people and shit.”

Jake blinks a couple of times and his face splits into an enormous grin. “Okay, see, now _that_ is awesome. Do you get a sidekick?”

“You want to be my sidekick?” Rosa asks, possibly not as skeptically as she means to sound.

He nods enthusiastically. “Uh, yeah! No, wait—not sidekick. But yes, I definitely want to slay vampires with you. Obviously. How is this a thing that we actually get to do?”

“That _I_ get to do.”

“Hey! No fair! I wanna hunt the undead and keep Gotham safe and stuff.” Rosa groans and tries to walk away, but he jumps in front of her again. “Please? Pretty please? Pretty, pretty please teach me how to slay vampires with you, and I promise I won’t tell anyone I saw what you do in your free time?”

“Fine. But no doing stupid shit and getting hurt, okay? I do this protect people, not to look cool.”

“But you do look cool!”

“I know.”

“Okay, yes. Yes! Definitely yes. Definitely ‘no’ to the getting hurt. One thousand pushups with the not getting hurt. So, when can we start? I may be a little drunk right now, or a lot, or maybe it’s the blood loss, but—“

“I’m gonna need another beer for this. You’re buying. And you should probably get a bandage or something.”

“Totally!” Jake beams, and he practically skips down the sidewalk back toward the bar. “Oh my god, I _love_ this cop thing already. Okay, we’ll call you Lady Van Helsing, mysterious and leather-clad defender of the night, and I will be Sir Jacob the Tenacious, killer of the _vampyres_ and slayer of the ladies, if you know what I’m saying. Codename: the Fancy Garlic. No, wait—”

***

The perp had made a run for it, and when Rosa catches up with him in the alley behind the station, they’re both surprised to see that the winter sun has started to rise—more so in his case, apparently, given that he vamps out almost immediately. He tries to dash in the other direction, away from the encroaching daylight; instead, he crashes straight into an unmoving Rosa.

She wraps her arms around him in attempt to stake him through the back, but he shakes Rosa off and dodges her as she lunges at him. He kicks her square in the chest, and it’s by luck more than anything that Rosa manages to grab a handful of his coat as she falls, taking him down with her. They struggle for almost half a minute before she catches sight of Scully, who’s standing under the fire escape.

His eyes meet hers for a second, and then he just blinks sleepily and sips his coffee.

“A little help here?” Rosa suggests, and it’s not clear that Scully so much as shrugs in response. The pause it takes her to realize that he’s not moving allows the vampire to grab her hair at the scalp and yank. “Okay, no,” she tells him, punctuating her feelings on the matter with a head-butt that dazes him just long enough for her to level her stake between them and finish him off. It’s one less collar for her, but it’s also one more vamp off the streets and not committing petty crime. So, mostly a win.

She’s dusting herself off when she notices Scully is still just standing in the same freaking place and sipping his coffee. “Thanks a lot, man.”

He shrugs. “Didn’t know you were the Slayer. That’s neat.”

“You tell _anyone_ what you saw, and I will put this through _your_ chest.” She twirls her stake for effect and pockets it. “Clear?”

“Sure,” Scully shrugs again. “Can you let me back inside? I got locked out, and now my coffee’s all cold.”

***

Rosa’s first case with Captain Holt involves staking out a men’s boutique whose owner’s other properties have been targeted by a series of messy break-ins. The new captain has made a point of working in the field with each of the detectives, which means Amy’s been practically vibrating for the last two weeks waiting for her turn. Rosa is just hoping that the case is demon-free, because Holt’s attentiveness means he’s probably not going to overlook a pile of slime or a suspect that disappears after being stabbed. At least he seems to share her opinion on small talk.

They wait in silence in the back room, watching the security cameras scan the dark store. A rack of clothing wobbles onscreen, and Rosa catches a glimpse of what looks like a horn just behind the swaying collared shirts. It’s hard to tell with the lighting, but there may be an orange-tinted foot sticking out, too. She sighs quietly; so much for subtlety.

Holt notices the movement, too, and comments after a pause, “Detective Diaz, you may or may not agree, but I believe our suspect here is not…entirely human.”

Well. That helps. “Fyarl demon, I bet,” Rosa nods. “Whole case looks like one on Staten Island two years ago—the perp would send a Fyarl rampaging to cover the actual theft with a mess. Fyarls are good for that. Pretty common in New York, too.”

Holt looks surprised for a moment, and Rosa starts to think she might have misjudged his comment. But then he nods. “Good observation, Detective. What would you suggest we do to find the actual culprit?”

“Kill the Fyarl before it can cause any more damage,” she shrugs. “Then nab the perp when he comes in to find out what happened to his meal ticket.”

“Acceptable. Are you appropriately armed for this pursuit? My heyday of tangling with demons has past, and I’m told you have a…knack for this type of case.”

“Sarge told you?”

“I’ve been affiliated with the Watchers’ Council since my cousin Nikki was Called in the seventies. They’ve become somewhat less racist since then.” Holt gestures to the screen. “He’s headed for the front window. We need to move. Watch out for the mucus.”

It’s not a big store, and Rosa moves fast; she vaults onto the demon’s shoulders and yanks its head sideways by the horn, making it stumble away from the plate-glass window. She buries a silver knife at the base of the Fyarl’s exposed neck, and it freezes instantly. Rosa has half a breath to feel relieved before the now-dead creature falls over; she moves with its downward trajectory and lands neatly on her feet. “Too easy,” she mutters.

Holt, meanwhile, has a pimply, middle-aged man wearing a ratty Mickey Mouse t-shirt in a headlock. He looks up to check Rosa’s status and nods approvingly. “I see Sergeant Jeffords didn’t exaggerate your proficiency. We’ll tell the Council that the next Fyarl demon…‘snot’ a problem!”  

***

Rosa has five minutes left on her break, and she’s not opening her eyes or leaving Babylon until the alarm on her phone goes off.

Amy, however, has other plans and apparently no qualms about interrupting the Slayer’s quiet time, which Rosa knows because she says exactly that. Without taking off her eye mask, Rosa groans, “How are you even in here?”

Her resolve is audible. “It wasn’t hard…Boyle talks. And you’re a _vampire slayer_!”

“Ugh,” Rosa grumbles, finally removing her mask and sitting up. “Who squealed?”

“What? No one _squealed_. I just did my homework, and I got there eventually.”

“Name of your sex tape,” Rosa says automatically. Jake isn’t here to appreciate it, but Amy _had_ cut off her nap.

“What—no! I just noticed that a weird number of your arrestees ended up in cells with east-facing windows, and then they’d be gone by the morning shift. And then I cross-referenced your arrival at the Nine-Nine with murders involving barbecue forks, and it turns out that number’s gone way down since you got here.”

“Uh huh. Are we done?”

“And then I did some Googling, and…and you’re not denying it!”

“Fine. I am a vampire slayer. I hunt the undead when I’m not trying to nap in between dealing with regular, non-bloodsucking criminals. Stakes are in the third drawer of my desk if you need one. Happy?”

“Yes. No, wait—who else knows?”

“No one.  Secret identity.”

“You asked who squealed on you!”

Break officially over, Rosa hides her eye mask behind the sink and starts lacing up her boots again. “Jake, from the Academy. Scully saw me waste a guy one time. Terry—he used to be my Watcher, before Holt took over a few months ago.”

Amy’s eyes go Disney Princess-wide. “ _Captain Holt_ is your Watcher? No wonder you get to meet with him so much! I’ve been trying—it’s always good to get in the extra face-time—but you…”

Rosa sighs. Jake’s got more in common with this woman than either of them would like to think. “Do you want me to teach you how to slay a vampire?”

Amy is so eager to accept that Rosa would, in this moment, honestly prefer having to deal with a whole nest of hybrid demons over one energetic new protégée, but at least she’ll probably take it more seriously than Jake had.

***

“You get that installing window locks isn’t especially hard or expensive, right?”

Gina smiles and pats Amy on the head. “Oh, Amy, yes, but you guys did _such_ a good job on my last apartment, and we both know you didn’t have other plans this evening.”

“What the hell is this?” Rosa asks, pointing to a bundle of herbs nailed near the front doorway. “You know this isn’t going to do…whatever you think it’s going to do, right?”

“Shh, shh. Rosa, I know you are a confirmed skeptic when it comes to the supernatural elements that walk among us, but rest assured that you are wrong. And I _have_ prepared for all contingencies. It should come as no surprise that my blood flows particularly hot and spicy, and that the _vampyre_ population of the New York metropolitan area is particularly attracted to it. Therefore…” Gina produces a wooden box from the depth of her coat closet and offers it to Rosa.

It looks and feels like a crappy movie prop. Rosa rifles through the contents: holy water, wreaths of garlic, and a shrink-wrapped pocket Bible. Not a stake, silver, or anything flammable in sight. Of course. She sighs and hands the box back to Gina. “All this crap’s gonna do is piss someone off. And nailing basil to your door just makes it smell good.”

“Not to mention,” Amy pipes up. “A vampire would need to get invited inside to be able to attack you here, so keeping all that stuff in a box in your closet isn’t really the safest or most effective—”

Gina cuts her off with an index finger pressed to Amy’s mouth. “Amy, sweetie, have you ever even _read_ a book? The Lonely Ones go where they please. And they please to get a taste of _this_.” She gestures to herself, then throws her hands up in some sort of defeat and floats toward her bedroom, presumably to find the book in question.

Amy pulls a vial of body glitter out of the box and casts a worried look at Rosa. “Twilight…isn’t accurate at all. Uh, right?”

Rosa snorts; the whole franchise is so bad that’s it’s not even worth actually laughing at. Barely any blood, even less violence, and the sparkling thing just made her mad on behalf of the undead. “No. Absolutely not.”

“We should probably tell her, though, right? Even if there’s not anything actually, uh, spicy in her blood?”

“Ugh, probably,” Rosa says. “Like she’ll believe us. What kind of woman doesn’t have a crossbow?”

**Author's Note:**

> [Fyarl demons](http://buffy.wikia.com/wiki/Fyarl_Demon) are indeed fairly active in New York City and extremely vulnerable to silver.
> 
> Be sure to leave kudos for [raktajinos](http://archiveofourown.org/users/raktajinos)'s [fabulous artwork](http://archiveofourown.org/works/4083433)!
> 
> Thanks as always to [ilostmyshoe](http://archiveofourown.org/users/ilostmyshoe) and [red_b_rackham](http://archiveofourown.org/users/red_b_rackham) for beta-reading, well, everything.
> 
> This fic would not exist without [stillscape](http://archiveofourown.org/users/stillscape) and [diaphenia](http://archiveofourown.org/users/diaphenia), who are incredibly talented when it comes to writing sitcom characters and should always be listened to on such matters.

**Works inspired by this one:**

  * [ART for 'Hello Flying Fatality'](https://archiveofourown.org/works/4083433) by [raktajinos](https://archiveofourown.org/users/raktajinos/pseuds/raktajinos)




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